Dash-pot for valve-gears



No. 6H,337. Patented Sept. 27, |898.

- C. E. SHADALL.

DASH POT FOB VALVE GEARS.

(Application led Mgr. 19, 1898.5

(No Model ml E u v mi NTTED STATES `PATENT i EErcEm CHARLES EDWARD SHADALL, OF MILWAUKEE, WISCONSIN, ASSIGNOR TO THE FRICK COMPANY, OF WAYNESBOROUGH, PENNSYLVANIA.

DASH-POT FOR VALVE-G EARS.

SPECIFICATION forming part of Letters Patent No. 611,337, dated September 27, 1898.

Application filed March 19, 1898. Serial No. 674,478. (No model.)

To @ZZ whom t may concern.-

Be it known that I, CHARLES EDWARD SHA- DALL, a citizen of the United States, residing at Milwaukee, in the county of Milwaukee and State of W'isconsin, have invented certain new and useful Improvements in Dash- Pots for Valve-Gears, of which the following is a specification.

My said invention consists in certain iinro provements in the construction and arrange ment of parts of a dash-pot for the valve-gear of engines, especially Corliss engines, the improvements relating especially to means for regulating the ingress and egress of air to and I5 from the vacuum-chamber during the operation of the engine, as will behereinafter more particularly described and claimed.

Referring to the accompanying drawings,

which are made a part hereof and on which similar letters of reference indicate similar parts, Figure l is a View showing a portion of a steam-cylinder of an engine of the character mentioned, with the tripping valve-gear Ymechanism shown in elevation and the dashz 5 pot, which constitutes the subject-matter of my said invention, in central vertical section; Fig. 2, a central vertical section through said dash-pot on a larger scale, and Fig. 3 a similar view of the regulating device on a still larger scale.

In said drawings the portions marked A represent the dash-pot cylinder, B the plunger, and C the regulating device.

The cylinder A is in the form of a cup, being formed with a closed bottom and open top, with an interior surface suitable for the plunger to operate in. A flange a extends out from one side at its bottom, and a flange a surrounds it midway its height. An air-port a2 leads from the bottom of said cylinder horizontally out into the iiange CL, and a vertical perforation co3 leads from said port a* to the top of said iiange. Said perforationa3 is of a size at its top to receive the regulating-valve C and isformed near its bottom with a seat a4 for the lower end of said valve. Directly in line with said perforation is a perforation in the ange a', in which the upper end of said valve C is mounted by means of a screw- 5o threaded connection, as shown.

The plunger Bis in effect a solid cylinder tting closely within the cylinder A, packingrings bbeing set into a circumferential groove therein to insure an air-tight joint between said parts. It is shown and is preferably formed hollow by means of a well-known method of casting to save metal and reduce its weight. On its top is formed a socket to receive the ball on the lower end of the. rod 1, which connects it to the valve-gear, a ball- 6o and-socket joint between said partsbeing preferable. i

The regulating valve or device C consistsv of a tube, eXteriorly screw-threaded near its Y top,mounted in the screw-threaded perforations provided therefor in the flange a on the side of the cylinder A. Its eXtreme top is of a form to admit of its ready adjustment by means of a wrench or the hand. Its lower end is mounted in the vertical perforation a3 7o in the ange a and adapted to slide up and down therein as it is adjusted by being turned in its screw-threaded seat in iiange a. j Its eXtreme lowerend is ground to form a valveface of usual form and is adapted to seat on the valve-seat a4, as before mentioned. At a point which will be above said flange a transverse openings c lead from its hollow interior to the outside. A vertical perforation formed with a valve-seat around its top leads from 8o the port a2 to within the part C. A valve C is mounted on said valve-seat and is formed with a stem c', which extends up for a distance therein. Guide-rings c2 extend out radially and hold it in a true vertical position in the tube. A shoulder c3 is formed within said tube a short distance above the top guidering to limit the upward movement of said valve. An adj usting-stem C2 is mount-ed in the upper part of said tube by means of screw- 9o threaded connection and extends down to within a short distance of the upper end of said valve-stem c. A coiled spring c4 is interposed between said part C? and the valve, surrounding a lug on each, which keeps it in place. Set-screws a5 and c5 serve to lock the parts C and C2 in the desired adjusted position, as will be readily understood. The operation of my said invention is as follows: As is well known, when the plunger roo is drawn out by the operation ofv the valvegear a partial vacuum is formed in the cylinder A beneath it, the extent of said vacuum being regulated by the device O, as it is seated more or less on the seat d4, sufficient air being allowed to be drawn in to form a suitable cushion onlthe return movement of the plunger. mechanism operates at the top the vacuum pulls said plunger quickly to close said valve, the air in the bottom of cylinderA being suficient to check it as it approaches the limit of its movement and prevent the noise, jar, or wear that would otherwise result. The pressure of the plunger upon said air, however, forces it 'against the valve C and operates to lift said valve sufficiently to permit said air to escape through the opening c and allow said plunger to settle to its seat in the cylinder A. The spring c4 operates to hold said Valve C closely to its seat except when its pressure is overcome by the greater pressure of the air beneath. To adjust this pressure by means of the stem C2, so as to secure the best results, is but a moments work, as also is the adj ustmentv of the device C. Both of these means for effecting the required adj ustment being located on the outside of the device, at all times within easy and convenient reach, the adjustment is effected whenever desired without in any manner disturbing the other parts of the dash-pot, as has` been necessary in other constructions in common use. Much time and labor and conse- As the disengaging-gear of the valve l. A dash-pot consisting of an open-top cylinder, a plunger mounted therein connected with the valve mechanism at its top, a port leading from the lower end of said cylinder beneath said plunger to the outside, a valveseat formed on the outside around said port, an adjustable regulating-valve therein formed hollow and having a port communicating with said first-mentioned port, avalve-seat around the outer end thereof, a spring-mounted valve therein, and separate means for adjusting said two valves, both on the outside of the dash-pot, substantially as set forth.

2. In a dash-pot, the combination, of the open-top cylinder A, the plunger B therein connected to the valve mechanism, a port a2 being formed leading from the lower end of cylinder A to the outside and having a valveseat formed around its outer end, the valve C formed screw-threaded and mounted in a screw-threaded perforation in a part on the side of said cylinder A and seated in said valve-seat, said valve C being formed hollowr and having a port which communicates with port a2, the spring-mounted valve C mounted in'a seat formed at the outer end of said port, and the adj listing-screw C2 for regulating the pressure of the spring on said valve, substantially as set forth.

In witness whereof I have hereunto set my hand and seal, at Milwaukee, Wisconsin, this 5th day of March A. D. 1898.

CHAS. EDWARD SHADALL. [n s] Vitnesses:

RICHARD ELsNER, EMMA ELsNER. 

